Phonograph stylus



Jan. 22, 1952 BAUER 2,583,289

PHONOGRAPH STYLUS Original Filed Aug. 30, 1947 INVENTOR. Blfjdl7lill 5. Bauer Y dzzi'ys Patented Jan. 22, 1952 v UNITED STATES PATENT OFFICE PEIQNOGRAPH STYLUS Benjamin B. Bauer, Oak Park, Ill., assignor to Shu e. Broth rs, In p ra e Chi a o. 11-, a corporation of Illinois Original application August 30, 1947, Serial No. 771,433. Divided and this application April 30. 1949, Serial No. 90,688

1 Claim. (01. 274-38) 1 I .2

Th s a plica ion is a d isi n of the app1icaat r ght n les here o. s re ati e y p rm nen y ti n of Ben min B- au r, erial N 71,433, attached t e t rsion membe The tu has iiled August 30, 1947, for Phonograph Apparatus. hole at its lower end into which one end of and the invention hereof relates to a, stylus for the stylus is relatively easily receivable. reproducing sound from records, it being an ob- It is a further object of the invention to pro ject of the invention to provide an improved vide an improved stylus whereby the stylus may stylus of this character. be easily and accurately aligned in proper play- Phonosraph t ns at evi e or r pr d s p s t ni h t ing sound from records, termed pickups, frc- In carrying out the invention in one form, a

quently are in the form of cartridges which com- 10 laterally rigid and vertically resilient record en- .prise a casing having a translating element and gaging stylus is provided comprising an attaching a coupling structure therein. Terminals in the portion, an ofiset portion extending at an angle form of prongs connected to the translating eleto the attaching portion, and a curved member me it ex nd from one end o the casi for e n in r m h o s t p r i d terminal;- n r pi i sert on i to co re p n ng sock 1 in i a e d engaging po n he t c n in the phonograph tone arm, A record engaging portion, the ofiset portion, and the curved memneedle or stylus is arranged exteriorly of the casber each have a ratio of transverse dimension ing adjacent the other end for iollowing record to vertical dimension substantially greater than grooves, the stylus being attachable to the couunity.

pling structure by means of a screw, for example, For a more complete understanding of the inusually also projecting from the casing where it vention, reference should be had to the acoomis engageable by hand or with a tool. The coupanying drawing in which:

pling serves to transmit mechanical movements Figure 1 is a sectional view of a phonograph or some function thereof from the stylus to the pickup including a stylus embodying the inventranslating element, and the translating element tion;

serves to convert the transmitted mechanical Fig. 2 is a top plan view of the pickup shown in movements into electrical variations which are Fig. 1 with the top cover removed; transmitted through the cartridge terminals to Fi 3 s a fragmentary View Of 1 011 a the phonograph amplifier or other reproducing larger scale, partially in section and partially device. For high quality reproduction, the sound broken away;

output from the phonograph should be substan- Fig. 4 is a view, partially in section and partially free from extraneous noises such as needle tially broken away, taken Substantially in the and record talk, and needle hiss, the former direction of arrows 44 of Fig. ,3; and

being sounds radiated directly to the atmosphere Fig. 5 is an end elevational view looking at the because of the vibrations of the stylus, the coustructure of Figs. 1 and 2 from the left.

pling structure, and the record itself, and the Referring more particular to the drawing, the latter being sounds caused by surface imperfecinvention is shown embodied in the stylus 36 of tions of the record and may pass through the a phonograph pickup I0, the pickup comprising pickup and phonograph. a casing II and a translating assembly l2 in- The width of the groove in phonograph records 40 side thereof. Casing H comprises couplemenvaries, and when the width decreases, a compo tary top and bottom members 13 and I 4 respecnent of force upward is produced on the stylus tively, these members being formed by any well and the pickup in general. This effect may cause known process, such for example as by stampfluctuations of the stylus in the groove which is ing or casting, and may be made of any mateundesirable in high quality reproduction, and it rial, such for example as brass, aluminum or is a further object of the invention to provide plastic. As shown, casing members l3 and M an improved stylus having vertical compliance are substantially identical with each other, are

or resilience whereby extraneous noises due to rectangular in outline, and when placed together such effects are substantially prevented from form essentially a forward compartment and a reaching the translating element. 7 rearward compartment which contain different In pickups oi the character described, a tor.- portions of the translating assembly l2, holes slcn member is arranged internally of the casebeing provided through the casing members ing for actuating the translating element, such whereby rivets l5, l5 and i! may be inserted for example as a crystal, and an arm or stud. for holding the pickup in assembled relation.

which extends through the casing substantially 1 Translating assembly I2 comprises a frame l8,

a piezoelectric element I9, such as a Rochelle salt crystal, and a coupling structure including torsion member 2! connected to frame l8. The frame I8 is generally trapezoidal in outline, may be formed from a flat piece of material bent into the configuration shown, and is provided with three openings, these being respectively at the rear of the frame and along each side. Crystal 19, which may be sealed from the atmosphere by a protective coating 22, is held within the openings in frame l8 by any well known means, such for example as cement, the two side members of frame I8 being movable relative to each other whereby to distort the crystal and consequently produce an electrical output. Welded to the front ends of the frame members are a pair of weights 23 for predetermining desirable vibration characteristics-of the frame and the cooperating structure.

While the active element of the translating assembly l2 has been shown as a piezoelectric element l9, it will be understood that this is exemplary only and that other suitable transducing elements, such for example as magnetic units, condenser units or photoelectric units, may be used.

The torsion member 21 is a relatively stifl member and is T-shaped in outline, the T end thereof being received between prongs on the front ends of the side members of frame l8. A rubber spacer 24 is placed between the end of torsion member 2| and the prongs whereby the coupling between frame I 8 and torsion member 2| is resilient. Hence, the movements of torsion member 2! are transmitted to frame is and crystal I 9 with decreased amplitude, relatively speaking. This is done because of the fact that the crystal maybe very stiff and distortions of relatively smaller amplitude may be desirable.

The mechanism for transmitting motion to the piezoelectric element 19, including the frame I8, is described fullv and claimed in Bauer United States Patent 2,513,269.

In the forward compartment of casing II, a downwardlyprojecting stud 25 is rigidly attached to torsion member 2| to form part of the coupling mechanism. As shown, the stud is attached to the torsion member by rivetin over, but this is by way of example only since other well known means may be used. The stud is made of some light metal, for example aluminum, in order that the inertia of the coupling mechanism may be kept at a minimum. It projects through an opening provided in the bottom member I4 of the casing.

A pair of resilient rubber bearing members 26 and 21 support torsion member 2| within the casing l i, the bearing members being held within the forward portion of the casing by journals formed by indenting the casing material as shown. Due to the rubber bearings or washers, the torsioin member may have slight movements both vertical as well as'horizontal, and its rotational movements are resiliently resisted, this being enhanced by the fact that torsion member 2| may be rectangular in cross section and therefore have a firm grip within the rubber bearings.

Forwardly of the rearward chamber there is a pair of clamping members 28 and 29 ly One on each side of the torsion member and bearing against the inside of the housing members 13 and I 4. Damping members 23 and 29 may be formed of substances known as elastomers, which substances have some resilience as well as the ability to absorb energy and thus supply some restoring force to torsion member 2| in addition to damping undesirable resonances thereof. At the rear of frame l8 there is a pair of support members or pads 3| and 32 formed of resilient substances such as elastomers whereby to resiliently support frame l8 and at the same time provide damping for undesirable resonances. The members 2B, 29, 3| and 32 may, for example, be made.

of Du Pont Pyralin, Type X-24.50.

Referring to Figs. 3 and 4, the stud 25 is provided with a hole 33 adjacent its lower end, which end is threaded to receive a nut 34. Nut 34 may be slotted or hexagonal, for example, for tightening with a wrench or it may be knurled, for example, for tightening with the fingers. Extending through hole 33 is the shank 35 of the record engaging stylus or needle 36.

The stylus 36 includes a curved portion 31 extending from shank 35 through an offset portion 38 which extends downwardly at an acute angle to the shank, the curved portion terminating in a record engaging point 33. The stylus cross section' is generally uniform and is substantially rectangular with a horizontal dimension considerably greater than the vertical dimension so that the stylus is vertically resilient and laterally stiff. As shown in the drawings, the ratio of the horizontal dimension to the vertical dimension is approximately 2. The curved portion 31 renders the stylus even more rigid laterally so that lateral movements of the point 39, when following a record groove, are transmitted virtually directly to the stud 25 without lateral distortion or bending of the stylus along its length. The

stylus may be formed of any suitable material, such for example as carbon steel, and may be formed by stampin from a round wire. The point 39 may be of hardened steel forming a direct part of the stylus material or it may be a hard point such as sapphire or diamond attached to the stylus.

When vertical forces are exerted downwardly on stud 25 and stylus 36, the curved portion 31 thereof bends somewhat along its length, but the major portion of the deflection or bending takes place adjacent the offsetting portion 33. Small vertical movements, such as due to the pinch effect already referred to, are taken account of by the vertical resilience of the stylus. When, however, substantially larger forces are exerted on. the point 39, these occurring for instance when the tone arm is dropped onto the record, it is desirable that deflections of the stylus beyond a predetermined amount be prevented in order not to exceed the elastic limit of the stylus as well as to prevent injury to the point. This is accomplished by the provision of tusks M on each side of point 39 and terminating a short distance there above, the tusks being rigidly attached to the casing ll. Whenthe stylus deflects due to large forces exerted thereon, the lower ends of the tusks come into contact with the record surface and thereby prevent deflection of the stylus beyond a predetermined amount.

In order to be able to align stylus 36 properly without the need of exercising unusual skill, the construction of the lower end of stud 25, nut 3 and shank 35 are such that the shank 35 may be inserted within hole 33 and the nut 34 tightened with the assurance that the stylus will be in the optimum position. According to the invention, thisis accomplished in one manner by forming hole 33, such as by drilling, with its axis parallel to the axis of torsion member 2!. The shank 35, being relatively rectangular in cross section, has two upper edges 42 and 43 which engage the surface of hole 33 along lines which also are parallel to the axis of the torsion member. The underside of shank 35 is flat and the upper surface of nut 34 is flat. Moreover, the axis of stud and that of nut 34 is at right angles to the axis of torsion member 2|. The upper surface of nut 34, in addition to being fiat, is also at right angles to the axis of stud 25. Accordingly, when nut 34 is tightened against the flat undersurface of shank 35, the upper edges 42 and 43 thereof are forced against the upper surface of hole 33. Since the axis of hole 33 is parallel to the axis of torsion member 2|, the shank 35 of the stylus is held parallel to the axis of the torsion member, and since the coacting surfaces of nut 34 and shank 35 are flat, the stylus is held to lie substantially in a vertical plane containing the axis of the torsion member, and consequently the point 39 is maintained in the proper position for engaging the record surface.

The axis of stud 25 being at right angles to that of the torsion member, tightenin the nut 34 to hold the stylus tends to produce only lateral forces upon the end of torsion member 2| connected to frame l8, and not rotational forces exerted about its axis. Distortions of frame l8 are thus lacking when nut 34 is being tightened, and consequently no distortions of crystal I9 occur. Hence there is no disagreeable noise produced in an operating phonograph when the stylus is being changed and there is no danger of applying damaging forces to the crystal.

The offset portion 38, in addition to providing desired vertical resilience for the stylus, by coming up against nut 34 prevents shank 35 from being pushed through hole 33 beyond the optimum point. Hence, the position of the needle in hole 33, both as to its position lengthwise of the pickup and its proper position for playing a record, is automatically taken account of.

When the pickup is in use, the point 39 of the stylus engages the groove of the record and the lateral undulations thereof are transmitted by means of the stylus and stud to torsion member 2!. Rotations of the torsion member effect distortions of frame is and consequent distortions of crystal I9 to produce output as already described.

The stylus 36 is a small light member, its transverse dimension for example being of the order of .03 inches, and the weight of stud 25 may be made small through the use of light weight material. introduced by the stud 25 and stylus 36 may be Thus, the rotational moment of inertia kept small. The maximum transverse dimensions of the torsion member 2! also being made small, the rotational moment of inertia introduced by this portion of the couplin system is also small. Accordingly, the total moment of inertia may be kept relatively small and transverse movements of the point as are transmitted relatively faithfully to crystal l9. Large amplitudes of vibration at natural frequencies caused by the resilience of stylus 35 and the mass of stud 25 and torsion member 2! are largely damped out through the use of the damping members 28 and 29.

The output of crystal I9 is carried by means of conductors inside of shields 44 and 45 to prongs 46 and 4'1 for conduction to the phonograph amplifier, the prongs being supported in an insulating member 48 forming a closure for the rear end of casing ll Prong 46 is grounded to casing I I by the conducting strip 49.

The invention having thus been described, what is claimed and desired to be secured by Letters Patent is:

A stylus for engaging a record groove having lateral undulations, comprising a shank portion, a downwardly curved point-carrying portion extending generally obliquely with respect to the shank portion, said shank portion being substantially flat in a plane lying transverse to the direction in which said point-carrying portion extends, said stylus being relatively thin in a vertical direction and being relatively wide and of substantially uniform width in a horizontal direction, an intermediate offset portion between and connecting said shank portion and said point-carrying portion and also oblique to said shank portion, said point-carrying portion being curved in the direction of its length and with its convex surface facing away from the record, and a point at the end of said point-carrying portion and forming substantially a continuation of said curve.

BENJAMIN B. BAUER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,290,295 Muller Jan. 7, 1919 2,320,416 Dally June 1, 1943 2,328,889 Capps Sept. 7, 1943 2,476,414 Hutter July 19, 1949 2,480,907 Dally Sept. 6, 1949 2,509,356 Kilgour May 30, 1950 

